Driving mechanisms for circuit breakers



March 5, 1957 H. A. HlDDE NIJLAND 2,784,270

DRIVING MECHANISMS FOR CIRCUIT BREAKERS Filed April 13, 1954 FIG] { fiRIVIN'G' MECHANISMS FOR CIRCUIT: BREAKERS Hendrik Arend Hidde Niiland', Laren, Netherlands, as-

signor to N. V. oq,'Utrecht, Netherlands Application April 13, 1954, Serial'N'o. 422,906

Claims priority, application Netherlands April 25, 1953 4 Claims. (Cl. 200-78) The invention relates to a driving mechanism for an electric circuit breaker comprising at least one high speed opening and. closing switching contact carrying movable part, one ormore springs for the closing movement of said contact and one or more springs forthe opening movement thereof, said springs being adapted tobe tensioned' by means of a manually or a motor driving operating member and to be kept under tension by means of locking devices which automatically assume their locking positions during the tensioning of the springs, said locking devices; being able to be released for theoperation of the circuit breaker. I

In the known mechanisms of this type-thesprings for the closingv movement and those for the opening movement of the circuit breaker are generally tensioned successively and the closing operation is: carried out by an closing springs and a locking device keeping these springs under tension after their tensioning to a stationary'part of the mechanism, said intermediate member 7 being adapted to be moved by the operating member'in. a directionin which all springs are broughtund'er'tension simultaneously.

Preferably the driving mechanism according to the invention is constructed in such a manner, that at least between the intermediate member and a stationary of the driving mechanism a togglelever is provided; which constitutes both a driving memberfor the intermediate member and a locking device for the closing spring, the operating member being so coupled with the toggle lever as to move said leverinto thelocking position during its movement in one, direction and, when approaching its startingpositibiidutihg its movement in the opposite direction, to release the toggle lever from its locking position whereby the closing springs are permitted to. close the circuit breaker.

In order to prevent that owing to premature operation of the locking device for keeping the opening springs under tension the intermediate member is drawn towards its starting position by said opening springs while there is no connection with the movable part of the circuit breaker so that this part remains stationary, it is recommended to provide a third locking device adapted to keep the intermediate member in the position in which all springs are tensioned, should the locking device for the opening spring be prematurely released.

These and other features of the invention will be elucidated with reference to the accompanying drawing which illustrates a driving mechanism according to the United States Patented Mar. 5, .1957

2 invention in. three difierent conditions tion.

Figure 1' shows; the circuit breaker in opened position.

Figure 2 showslan intermediate position.

Figure 3' shows the circuit. breaker. inclosed position.

In the drawing. 1 designates a switching rod adapted to be axially moved up and down and to cooperate with fixed switching. contacts 2, 3, to which,"in a manner not shown, the circuit to be closed and opened by. the circuit breaker is connected; The switching rod 1 is connected through an insulator 4 to an arm 5 of abellecrank 5,, 7 which is rotatably mounted on a pivot 6. In the opened condition of the circuit breaker, shown in Fig. 1', the arm 7 of. the bell-crank 5, 7, is in contact with a fixed abutment 8. The arm 7 is connected through one" or morejsprings 9 to the arm 10 of. a lever 10, 12 adapted to. be swung about a pivot 11. In Fig. 1 the lever 10, I2 lies with its arm 12 against a fined. abutment 13. The arm 12is coupled through one or more springs 14 to a stationary part 15 of the circuit breaker.

The two-armed. lever 10, 12 constitutes an intermediate member. which is adapted to be driven by an operating mechanism. This operating mechanism consists of a toggle. lever formed by the links 16, 17. and a handle 19, 20,.which is rotatably mountedon the shaft 18 and is capable to engage the link 17. To that end the arm 20 isprovidedwith a stud 21. adapted to engage the link 17 of'the toggleleven. The arm 7 of'the bell-crank..5,.7 isalso secured to a locking rod- 22.provided with.v a catch 23 which cooperates with a stud. 24 attached to the arm 10 of theint'ermediatemember 10, 12.

For the-operation of the driving mechanism having the task to ciose and toreopen the circuit breaker the handle 19, 20, is sw-ungabout its shaft counterclockwise. The result thereof, is, that thetoggle lever 16, 17 is moved through its stretched position against a fined abutment 25. Due to this movement'of the toggle lever the intermediate member 10, 12"is rotated counterclockwise about the pivot 11, whereby the springs 9 as well as the. springs14 are tensioned (Fig. 2). If the'handle19, 20 should be released. in theposition according to Fig, 2 the springs 9 and 14 are kept under tension, since the toggle-lever 16, 17 remains in its locking position. As soon as the intermediate member. 10, 12 has. reached the position, in which the springs9, 14 are .tensioned, the locking. rod 22. engages with its catch 23 the stud 24, so that the springs 9 for. the openingmovement of the circuit breaker are kept under tension.

The link 17 ofthetoggle lever 16, 17 constitutes-one arm of the. free rotatablebelr-crank 17, vL26 which is rotatably mounted on the shaft 18 of the handle 19, 20. When the handle 19, 20. is swung from its position showninFig. 2 in a clockwise direction it will engage with its stud 21 the arm 26 just before it reaches. its starting position. The result thereof is, that thetoggle lever 16, 17 is turned. out of its locking position, whereby the closing springs 14 are permitted to release their tension and to draw the intermediate member 10, 12 with high speed against the fixed abutment 13. Owing to this movement of the intermediate member the bellcrank 5, 7 is moved by the locking rod 22 into the position shown in Fig. 3. In this position the switching rod 1 interconnects the switching contacts 2, 3 and the circuit breaker is closed.

If it is desired to open the circuit breaker, it is neces sary to release the rod 22 from its locking position, so that the opening springs 9 are allowed to draw the bellcrank 5, 7 together with the switching rod 1 back to its starting position against the fixed abutment 8. The release of the locking rod 22 is carried out by means of an auxiliary device consisting of a rotary three armed lever or bell-crank 29, 30, 31, of which the axis of during its: opera- Q rotation is shown at 28. The arm 29 of said bell-crank is is loaded by a spring 35 and cooperates with a pawl 36,

37, which is pivotally mounted about an axle 38 and may be unlocked with the aid of a slidable rod 39 provided with a push-button 40. When the: handle 19, 20 is part, at least one high speed opening and closing switchswung counter-clockwise the three armed lever 29, 30, i

31 is moved and thespring 35 is tensioned and kept under tension, when the hook of the pawl engages the arm 31. At the same time the stud 34 of the arm 30 is lowered to such extent that the catch 23 of the locking rod 22 is free to engage the stud 24 of the intermediate member 10, 12 as soon as the springs 9 andr14 have reached their tensioned conditions. In order to open the circuit breaker itis only necessary to push the button 40. This results in releasing the pawl 36, 37 from the bell-crank 29, 30, 31 so that the latter if permitted to be rotated about its pivot 28 by the spring 35, the stud 34 lifts the rod 22 a bit and the lock of thetensioned opening springs 9 is released.

Fixed 'to the shaft 6, to which the bell-crank 5, 7 is attached, is an arm 41' provided with a hook-shaped end portion 42, which engages a stud 43 fixed to the intermediate member 10, 12 when the latter is in the position shown in Fig. 2 and the springs 9, 14 are tensioned.

It will be clear, that, if in the condition of the driving mechanism shown in Fig. 2 the push-button 40 should be erroneously operated, the opening springs 9 will be released by the locking rod 22, but yet the intermediate member 10, 12 can not be drawn back towards its starting position. This is firstly prevented by the toggle lever 16, 17 which is still in its locking position and secondly by the hook 41, 42. If, afterthe operation of i the opening push-button 40, the handle 19, 20 should be returned towards its initial position and the toggle lever :should be released thereby the intermediate member 10, 12 is still kept by the hook 42 in the position according to Fig. 2, in which the springs 9 and 14 are under tension.

Consequently, it is not possible that the intermediate member is drawn freely, towards its starting position by all springs together, whereby'the driving mechanism could easily be damaged. In order to correct the error made by the premature operation of the opening push button it is necessary to operate the handle 19,

'20 again so that the auxiliary device 28-40 is again tensioned and locked. i

' It will be obvious that the handle 19, 20 may be replaced by a motor gear. Together with the illustrated device for releasing the toggle lever 16, 17 from its locking positions by means of the handle 19, 20 or a motor gear an electromagnet for the closing of the circuit breaker may be provided, said. electromagnet operating on the toggle lever 16, 17 in any suitable manner. l opening the circuit breaker an electromagnet may be used,

Also for so that the circuit is adapted to be operated'from a distance.

What I claim is:

1. A driving mechanism for an electric circuit breaker comprising, in combination, a stationary part, a movable ing contact carried by said part, at least one spring adapted to be biased for the opening movement of said contact, at least one spring adapted to be biased for the closing movement of said contact, an operating member for tensioning said springs, locking devices comprising at least one toggle lever and a locking member associated with said movable part, said locking devices being adapted to move automatically into their locking positions during the tensioning of the springs by said operatingmember to keep the tensioned springs under tension, a movable intermediate member connected to said contact carrying movable part through said first-named spring and its associated locking member and to the stationary part of the mechanism through said closing spring and said toggle lever, said closing spring and said toggle lever being efiective to drive said intermediate member, and a free stroke coupling provided between said operating member and said toggle lever, whereby during its forward movement said operating member through. said toggle lever as defined in claim 1, wherein said operating member is a rotary member and wherein the toggle lever link re mote from the intermediate member is formed as abellcrank adapted to journal about the axis of rotation of the operating member, said operating member being provided-with a coupling part projecting into the spacebetween the arms of the bell-crank and said free stroke coupling being defined by thefree stroke of said coupling part between said bell-crank arms.

3. A driving mechanism for an electric circuit breaker as defined in claim 1, further comprising a third locking device provided between the contact carrying movable part and the intermediate member, said third locking device being adapted to keep the intermediate member in the position in which all springs are tensioned, should the locking device for the opening spring be prematurely released.

4. A driving mechanism for an electric circuit breaker as defined in claim 1, further comprising a swingable driving arm connected to the contact carrying movable part and adapted to drive the same, a second arm fixed to said driving arm, a catch provided on said second arm References Cited in thefile of this patent UNITED STATES PATENTS 1,724,776 Rankin Aug. 13, 1929 

